My research is centered around the sixteenth century and is mostly related to the exact sciences: mathematics, astronomy, etc. I have a special fondness for textual work. I know it is a bit old-fashioned, but I still believe that the close reading of ancient scientific texts is the true mark of scholarship in the history of science. I have engaged in other studies as well, broader and more theoretical. For example, I am interested in book history, in the study of material culture, and in the more theoretical aspects of the historiography of science.

Here's a brief list of my main Projects, with links to pages with more detailed information:

1. Pedro Nunes Complete Works (Obras de Pedro Nunes)

The publication of Pedro Nunes' Complete Works (Obras de Pedro Nunes) has been my most absorbing task in the past years.

This Project is reaching its final stages and its main objective -- the publication of all printed works of Pedro Nunes in a modern,

annotated edition -- has been achieved.

The following volumes are already published:

Vol. I: Tratado da Sphera & Astronomici introductorii de spaera epitome (2002), 320 pp.

Vol. II. De crepusculis (2003), 431 pp.

Vol. III. De erratis Orontii Finaei (2005), 409 pp.

Vol. IV. De arte atque ratione nauigandi (2008), 805 pp.

Vol. V. In theoricas planetarum Georgii Purbachii annotationes (2011), 465 pp.

Vol. VI. Libro de algebra en arithmetica y Geometria (2010), 576 pp.

For more information about this project, click here.

2. Francisco de Melo's mathematical works

I am working with Bernardo Mota on the edition of Francisco de Melo's mathematical works. We had been working with the copy at

the Biblioteca Nacional de Lisboa (Cod. 2262), but the recent find in Germany, at the Stralsund Municipal Archive, of the original

manuscript gave an added impulse to our work. The original manuscript is a remarkable item, truly the present for a King. It was

located by dr. Jürgen Geiss of the Staatsbibliothek Berlin. We set up an Internet site devoted to this project: Francisco de Melo and the Euclidean Tradition in Portugal.

For more information about this project, click here.

3. Old Libraries and Scientific books in Portugal

I have long been interested in Libraries and Books on scientific matters. I maintain a collaboration with the National Library in Lisbon since 2001. Together with the staff at the Rare Book Division (Reservados), headed by Lígia de Azevedo Martins, we prepared the Catalogue of fifteenth and sixteenth century books on science (see the Books page) and we set up four exhibitions at the National Library on matters related to science (see the Exhibitions page). We have also been working on the Collection of old scientific manuscripts (see below).

In the past years Luana Giurgevich (a post-doc at our group) and I engaged in a very ambitious study of old libraries in Portugal with the objective of mapping in sufficient detail the most important ancient collections of scientific books in Portugal and the way those books were used.

4. Leonard Thurneysser manuscript of Portuguese plants and animals.

Together with Thomas Horst (a post-doctoral researcher at our group) I have been investigating the circulation of scientific and technological knowledge between Portugal and Germany in the early modern period. The topic is not completely new, of course, but we are working with new documents, in particular an important and recently re-discovered manuscript by Leonard Thurneysser (1531-1596) written while at the house of the famous Portuguese humanist Damião de Góis. Prof. Bernardo Herold is also working with us and we are collaborating with the Staatsbibliothek zu Berlin.

5. Manuel Dias' Tianwenlüe 天问略

Rui Magone (in Berlin) is one of my best friends and an expert sinologist. I am working with him on the edition of the Tianwenlüe 天问略 [Epitome of Questions on the Heavens], a very important astronomical text written in China in 1614/15 by the Portuguese Manuel Dias. The Tianwenlüe 天问略 is famous because of this last page, where Galileo's telescopic observations (of 1609-1611) are described for the first time in Chinese. You can check the blog where we discuss our progress in detail. For more information about this project, click here.6. Translation of Ancient Scientific Texts

Together with some colleagues (Armando Martins, Bernardo Mota, Carlos Sá and Samuel Gessner, Helena Avelar, Joaquim Gaspar) I have been engaged in the translation of ancient scientific texts. We already translated Euclid's Optics and Catoptricts (in the Latin version of Zamberto), Theodosius's Spherics, Book III of Peurbach and Regiomontanus's Epitome of the Almagest, and we are now working on Johannes Werner's, Conics. We have also translated bits and pieces of Euclid, Autolycus and Diophantus, from Greek. We plan to publish some of these translations; others no. I have learned immensely from this effort and from the knowledge of my colleagues -- and it has been great fun.

For more information about this project, click here.

7. Science in glazed tiles (azulejos).

Together with Samuel Gessner (a former post-doctoral researcher at our group, presently a collaborator) I have been studying the mathematical/scientific imagery in eighteenth-century glazed tiles (azulejos) in Portugal. Some of our research has already been published in two papers and more will appear soon. See: Henrique Leitão and Samuel Gessner, "Euclid in tiles: the mathematical azulejos of the Jesuit college in Coimbra", Mathematische Semesterberichte, 61.1 (2014) 1-5; and Samuel Gessner and Henrique Leitão, «Una tribus ratio : Ikonographie der Wissensvermittlung und Selbstdarstellung der Jesuiten im Thesensaal des Kollegs in Lissabon», Mathematische Semesterberichte, 62 (2015) 1-6.